Chip resistor, and its manufacturing method

Abstract

A chip resistor includes: a pair of upper surface electrodes formed at opposing side portions of a rectangular substrate as opposed to each other with respect to a center line of the rectangular substrate extending in a direction connecting the side portions; a resistive element formed on the rectangular substrate to be electrically connected with the upper surface electrode pair; and a pair of end surface electrodes formed on end surfaces of the opposing side portions of the rectangular substrate and electrically connected with the upper surface electrode pair. The chip resistor further includes dummy electrodes formed individually at the opposing side portions of the rectangular substrate at positions corresponding to the upper surface electrode pair in the direction connecting the side portions.

1. A chip resistor comprising:
 a rectangular substrate having opposing side portions; 
 a pair of upper surface electrodes, formed at the opposing side portions of the rectangular substrate, respectively, opposed to each other with respect to a center line of the rectangular substrate extending in a direction from one side portion to the other side portion; 
 a resistive element, formed on the rectangular substrate, to be electrically connected directly to the upper surface electrode pair; 
 a pair of end surface electrodes, formed on end surfaces of the opposing side portions of the rectangular substrate and electrically connected to the upper surface electrode pair, respectively; and 
 formed individually at the opposing side portions of the rectangular substrate, so that the dummy electrodes are opposed to their counterpart upper surface electrodes with respect to the center line, respectively, wherein 
 the dummy electrodes are not connected directly to the resistive element. 
 
     
     
       2. The chip resistor according to  claim 1 , wherein the upper surface electrode pair protrudes farther inward than their counterpart dummy electrodes in the direction from one side portion to the other side portion of the rectangular substrate, respectively. 
     
     
       3. The chip resistor according to  claim 2 , wherein the end surface electrode pair is formed from the end surfaces of the opposing side portions of the rectangular substrate to a part on an upper surface of the rectangular substrate, so that the respective end surface electrodes cover substantially an entire surface of their counterpart dummy electrodes, respectively. 
     
     
       4. The chip resistor according to  claim 1 , wherein a glass coat for covering the resistive element, with such dimensions as to bridge over the dummy electrode pair, and a resin coat for covering the glass coat are formed on the rectangular substrate. 
     
     
       5. The chip resistor according to  claim 1 , wherein
 a glass coat for covering the resistive element, with such dimensions as to bridge over the upper surface electrode pair, and a resin coat for covering the glass coat are formed on the rectangular substrate. 
 
     
     
       6. A method for manufacturing a chip resistor, comprising:
 a step of forming a pair of upper surface electrodes, at inner positions of two opposing first dividing grooves, respectively, in each of a plurality of rectangular substrates formed on a sheet-like substrate, opposed to each other with respect to a center line of the rectangular substrate extending in a direction from one first dividing groove to the other first dividing groove, the sheet-like substrate having the plurality of rectangular substrates formed in a checkered pattern via the first dividing grooves and second dividing grooves; 
 at inner positions of the two opposing first dividing grooves, so that the pair of dummy electrodes are opposed to their counterpart upper surface electrodes with respect to the center line, respectively; 
 a step of forming a resistive element, on each of the rectangular substrates, to be electrically connected directly to the upper surface electrode pair and not directly connected to the pair of dummy electrodes; and 
 a step of forming end surface electrodes, on opposing end surfaces of a substrate strip obtained by dividing the sheet-like substrate along the first dividing grooves, so that the end surface electrodes are electrically connected to the upper surface electrode pair, wherein 
 the upper surface electrode formation step and the dummy electrode formation step are simultaneously conducted so that one of the dummy electrodes and one of the upper surface electrodes, on a rectangular substrate, are electrically connected to the corresponding one of the upper surface electrodes and the corresponding one of the dummy electrodes on an adjacent rectangular substrate via the first dividing grooves, respectively. 
 
     
     
       7. The chip resistor manufacturing method according to  claim 6 , wherein
 direction from one first dividing groove to the other first dividing groove, and 
 in the end surface electrode formation step, the end surface electrodes are formed so that substantially an entire surface of the dummy electrodes are covered with the counterpart end surface electrodes, respectively, by forming the end surface electrodes from an end surface of the substrate strip to a part on an upper surface thereof. 
 
     
     
       8. The chip resistor manufacturing method according to  claim 6 , further comprising:
 a step of forming, on the respective rectangular substrates formed on the sheet-like substrate, a glass coat for covering the resistive element, with such dimensions as to bridge over the dummy electrode pair; and 
 a step of forming a resin coat for covering the glass coat. 
 
     
     
       9. A method for manufacturing a chip resistor, comprising:
 a step of forming a pair of upper surface electrodes, at inner positions of two opposing first dividing grooves, respectively, in each of a plurality of rectangular substrates formed on a sheet-like substrate, in a direction along an extending direction of the first dividing grooves, by forming the upper surface electrode pair on an area substantially covering the two first dividing grooves in the sheet-like substrate, respectively, the sheet-like substrate having the plurality of rectangular substrates formed in a checkered pattern via the first dividing grooves and second dividing grooves; 
 a step of forming a resistive element, on each of the rectangular substrates, to be electrically connected to a part of the upper surface electrode pair and to be close to a part of the upper surface electrode pair other than electrically connectable parts; 
 a step of forming, on the each of the rectangular substrates formed on the sheet-like substrate, a glass coat for covering the resistive element, with such dimensions as to bridge over the upper surface electrode pair; 
 a step of forming a resin coat for covering the glass coat; and 
 a step of forming end surface electrodes, on opposing end surfaces of a substrate strip obtained by dividing the sheet-like substrate along the first dividing grooves, so that the end surface electrodes are electrically connected to the upper surface electrode pair.